Expert Answers: Figuring Out How Much Weight to Lift

Q | How do I determine how much weight I should be lifting?  

A | The cardinal rule for weight selection is that, once you’re comfortable with an exercise, you should choose a weight that’s challenging — but not impossible — to lift with good form for the prescribed number of reps.

When an exercise is brand new to you, finding the ideal resistance level takes some trial and error, says veteran trainer Nick Tumminello, author of Strength Training for Fat Loss. “At first, be conservative,” he says. “For the first week on any new program, choose weights that you can handle easily.”

After that break-in period, add weight based on the experience in your previous workouts. If your program calls for three sets of five reps on the deadlift, for example, and you easily completed that with 95 pounds last week, add 5 to 10 pounds to the bar this week. If you struggled to complete that programming, stick with 95 pounds until you can manage five reps on all three sets.

If you’re freewheeling it in the gym and not working off a prescribed plan, try using these guidelines for matching poundage with goals:

• Heavy weights are loads you can lift fewer than eight times with good form; they help you build strength.
• Medium weights are loads you can lift eight to 12 times; they help you build a combination of size and strength.
• Light weights are loads you can lift 15 or more times; they help you build endurance.

Remember that your body isn’t a machine: Some days you’ll feel strong and energized; others, drained and exhausted. Respect your body’s signals, and push harder or pull in the reins.

In the long run, listening to your body is the key to safe and steady progress in the weight room.